Objective-C KVC 自己主动转换类型研究

## Objective-C KVC 自己主动转换类型研究

apple非常厚道,kvc的时候帮我们做了一些类型转换,规律贴出来,给大伙參考參考

@interface Entity : NSObject

@property (nonatomic, copy) NSString *str;

@property (nonatomic, assign) int i1;
@property (nonatomic, assign) int i2;
@property (nonatomic, assign) int i3;

@property (nonatomic, assign) float f1;

@property (nonatomic, strong) NSNumber *num;

@property (nonatomic, assign) BOOL b1;
@property (nonatomic, assign) BOOL b2;
@property (nonatomic, assign) BOOL b3;

@property (nonatomic, strong) NSDate *date1;

@property (nonatomic, assign) NSTimeInterval t1;

@end

	// 数值的字串能够转成数值类型
    [obj setValue:@"2.4" forKey:@"i1"];
    // 非数值的字串不认识
    [obj setValue:@"a" forKey:@"i2"];
    // 仅仅认识特殊符号曾经的数
    [obj setValue:@"2014 10-24" forKey:@"i3"];
    
    // 这个转换过去是NSNumber类型
    [obj setValue:@1 forKey:@"str"];
    [obj setValue:@1.23 forKey:@"f1"];
    
    // 转去还是NSString
    [obj setValue:@"99" forKey:@"num"];
    
    // >= 1.0 为真, 1.0下面为假
    [obj setValue:@0.9 forKey:@"b1"];
    // >= 1.0 为真, 1.0下面为假
    [obj setValue:@"1.1" forKey:@"b2"];
    // true TRUE yes YES false FALSE no NO 都能够识别
    [obj setValue:@"TRUE" forKey:@"b3"];
    
    // 转去还是NSTring
    [obj setValue:@"2014-10-24" forKey:@"date1"];
    // 不认识
    [obj setValue:@"2014-10-24" forKey:@"t1"];
    
    // 结论
    // 数值类型的字串 to 数值 能够转行成数值
    // 类 to 类 不转换直接赋值